- IgA nephropathy (Berger nephropathy).

IgA nephropathy (Berger nephropathy)

Glomerular disease characterized by renal IgA deposits mostly in the mesangial area.

Etiology
Mucosal infection has been found to be associated with development of IgAN. Upper respiratory tract pathogen, like Hemophilus para influenzae, Coxsackie B4, Staphylococcus aureus, CMV, EBV, Enterovirus, have been found to cause IgAN.

PATHOLOGY

• Focal and segmental mesangial proliferation and increased mesangial matrix are seen in the glomerulus with few crescents.
• IgA nephropathy is an immune complex disease initiated by excessive amounts of poorly galactosylated IgA1 in the serum causing the production of IgG and IgA autoantibodies.

Clinical Features

• More often in male than in female patients.
• peak incidence between 10-30 years of age.
• Hematuria:

- There may be persistent hematuria or recurrent episodes of gross hematuria which typically resolves within days.
- Asymptomatic microscopic hematuria with or without proteinuria

• Gross hematuria often occurs within 1-2 days of onset of an upper respiratory or gastrointestinal infection
• Proteinuria is often <1000 mg/24 hr in patients with asymptomatic microscopic hematuria.
• Mild to moderate hypertension is most often seen in patients with nephritic or nephrotic syndrome, but is rarely severe enough to result in hypertensive emergencies.
• Normal serum levels of C3 in IgA nephropathy help to distinguish this disorder from poststreptococcal glomerulonephritis.
• Normal renal function
• Serum IgA levels have no diagnostic value because they are elevated in only 15% of pediatric patients.
• Flank or loin pain
• Fever may be present
• Not associated with systemic manifestations.

Renal biopsy
Immunofl uorescence or immunocytochemistry study shows glomerular deposition of IgA which is the hallmark of IgAN
 
Prognosis:

• Prognosis is good in most cases.
• Progressive disease to ESRD develops in 20-30% of patients 15-20 yr after disease onset.
• Poor prognostic indicators at presentation or follow-up include:

- Hypertension
- diminished renal function,
- significant, increasing, or prolonged proteinuria.
- A more severe prognosis is correlated with histologic evidence of diffuse mesangial proliferation, extensive glomerular crescents, glomerulosclerosis, and diffuse tubulointerstitial changes, including inflammation and fibrosis.
Treatment:

• No specific effective treatment.
• The primary treatment of IgA nephropathy is appropriate blood pressure control and management of significant proteinuria. Angiotensin-converting enzyme inhibitors and angiotensin II receptor antagonists are effective in reducing proteinuria and retarding the rate of disease progression when used individually or in combination.
• Fish oil, which contains anti-inflammatory omega-3 polyunsaturated fatty acids, may decrease the rate of disease progression in adults.
• Immunosuppressive therapy with corticosteroids is recommended: Corticosteroids reduce proteinuria and improve renal function in those patients with a glomerular filtration rate >60 mL/min/m2.
• Immunosuppression with cyclophosphamide or azathioprine has not appeared to be effective.
• Tonsillectomy not proven to reduce frequency of hematuria and renal disease progression
  
• Patients with IgA nephropathy may undergo successful kidney transplantation. Although recurrent disease is frequent, allograft loss caused by IgA nephropathy occurs in only 15-30% of patients.

References:

1. Corrie E. Chumpitazi, Manish I. Shah, 5-Minute Pediatric Emergency Medicine Consult,2012 pg 472-473
2.  Cynthia G. Pan and Ellis D. Avner , nelson textbook of pediatric 20ed ,
3.  Melissa A. Cadnapaphornchai, Gary M. Lum, Current diagnosis of pediatric 23th ed , CH24, Kidney & Urinary Tract.
4.  Scott K. Van Why and Cynthia G. Pan, Nelson Pediatric Symptom-Based Diagnosis.CH20,hematuria
5.  Oxford Handbook of Paediatrics 2nd ed  CH11 nephrology
6.  Bernardo Rodríguez-Iturbe, Behzad Najafian, Alfonso Silva, and Charles E. Alpers,Ch31, Acute Postinfectious Glomerulonephritis in Children, Pediatric Nephrology, 7th ed
7.   Moin A. Saleem, Jane Tizard, Jan Dudley, Carol Inward, Richard Coward, Mary McGraw, Disorders of the urinary system, Forfar & Arneil’s TEXTBOOK of PEDIATRICS, 7th ed

 

Ibrahim Samaha